Lateral flow assay systems have been extensively used as laboratory and point of care devices over the past forty or more years for clinical diagnosis of a wide variety of physiological conditions and disease states. The popularity stems mainly from such inherent useful characteristics as short assay times, high portability, convenient read-out options, ease-of-use, low cost, and often sufficient diagnostic accuracy.
Microarrays are powerful tools for sensitive multi-parameter biochemical analysis. Recently, it has been demonstrated that microarrays printed onto nitrocellulose substrates can be employed for multiplexed lateral flow analysis. While multiplexed lateral flow assays could prove valuable for instance in comprehensive on-site diagnostic devices, immunochromatography as it is employed in lateral flow assays presents very different conditions for analysis when compared to well-based planar microarray assays.
The influence of kinetic parameters on adsorption/desorption and breakthrough curves in affinity chromatography has been studied extensively. The time-dependent shape of a travelling analyte zone through a column subsequent to a plug injection has been shown to vary deterministically according to the kinetic constants of the interaction between reactant and binder on the solid phase.
Flow assay methods and devices are today only aiming to measure, quantitatively or qualitatively, the presence of a certain substance, WO2003025573 ('573) and WO2007063423 ('423). Both document '573 and '423 uses multispot arrays to improve the statistics. However the depletion of reactant in upstream spots, resulting in downstream spots displaying lower levels of reactant binding in most cases, indicates that downstream spots are unsuitable as replicates of the first.